[Feature]: Expose publishedPullRequestHasOpenedAt in openclaw code run --json output

[zhyongrui]

Summary
Add one stable top-level boolean field to openclaw code run --json named publishedPullRequestHasOpenedAt.

Problem to solve
Downstream tooling currently has to inspect draftPullRequest.openedAt directly just to decide whether the workflow run includes this signal. That is awkward for simple JSON consumers.

Proposed solution
Update src/commands/openclawcode.ts so the JSON output includes publishedPullRequestHasOpenedAt: boolean.

• true when draftPullRequest.openedAt resolves to true or contains at least one entry
• false otherwise

Add or adjust unit tests in src/commands/openclawcode.test.ts to cover both cases.

Impact
Affected users/systems/channels
Tools and scripts that read openclaw code run --json.

Severity
Low.

Frequency
Whenever downstream tooling needs a stable boolean instead of reimplementing nested truthiness or array-length checks.

Consequence
Without the derived boolean, simple consumers keep reimplementing the same nested truthiness or array-length check logic.